This application is not related to any pending United States or international patent application.
This application is not referenced in any Microfiche Appendix.
Valves are primarily used to close or open liquid or gas flow or to regulate the volume of flow. There are many types of valves, including gate valves, plug valves, ball valves and so forth. The valve of this invention has a different applicationxe2x80x94that is, to close-off flow in the event the flow rate through the valve exceeds a preselected limit. The valve can be used anywhere a liquid commodity is being pumped.
One use of the valve of this invention is to close or open flow from a large container under pressure to a smaller container, such as when delivering propane or butane from a tank truck to a residential location. For this purpose, a flexible hose is usually employed to extend from the tank truck to connect to a smaller container, usually through a meter, for delivering liquid to the smaller container. If for any reason the flexible hose or equipment connected to the flexible hose should rupture, a large quantity of liquid (and/or gases) could be suddenly released to the environment. This imposes a serious problem, particularly if the liquid is hazardous to health, combustible or most important, explosive. The valve of this invention provides a means of closing fluid flow if the rate of flow exceeds a preselected limit. By xe2x80x9cfluidxe2x80x9d flow, is meant throughout this disclosure, either liquid or gas or a combination of liquids and gases.
This is just one example of the use of the valve of this invention. The valve can be used not only with flexible hose connections but, also at storage tanks, loading and off-loading facilities and so forthxe2x80x94that is, in any application in which flow needs to be terminated when the flow rate becomes excessive.
Others have provided valves to close flow in the event of emergencies. As an example, U.S. Pat. No.4,278,102 entitled, xe2x80x9cDISASTER ACTIVATED SHUT-OFF VALVExe2x80x9d that issued on Jul. 14, 1981 to Kelley et al. provides a valve that is closed when the valve is subjected to shock or vibration such as produced by an earthquake.
U.S. Pat. No. 4,880,030 entitled, xe2x80x9cSAFETY FLOW CONTROL FLUID SHUTOFF DEVICExe2x80x9d that issued on Nov. 14, 1989 to Terry provides a device to cut off fluid flow in the event of excess consumptionxe2x80x94that is, excess of fluid flow rate.
For other examples of prior art relating to devices to control excess fluid flow reference may be had to the following U.S. Patents:
The invention herein provides an excess flow shut-off valve, the invention providing a valve body having a fluid flow passageway through it. A closure ball is rotatably supported within the valve body, the ball having a flow passageway therethrough in the general form of a traditional ball valve. The ball has a first rotational position in which the ball flow passageway is in alignment with the valve body flow passageway permitting flow through the valve. This is the valve open position. In a second rotational position, the ball flow passageway is out of alignment with the body flow passageway thereby preventing flow through the valve. This is the valve closed, or shut-off position.
A closure spring biases the ball towards the secondxe2x80x94that is, the shut-off or closed position. The closure spring is preferably in the form of a coil spring that is wound around a stem extending from the ball.
An actuator has a first position holding the ball in the open condition. The actuator is preferably in the form of a slidable elongated member having one end that extends within a notch in the ball surface, the notch being spaced away from the passageway through the ball. When the ball is rotated against spring tension to the open position the actuator extends within the notch so that the ball is held against the closure spring bias in the open condition.
A paddle extends from the actuator into the body flow passageway. This paddle in the form of a surface that extends radially from the actuator and is impinged upon by fluid flow through the valve.
An actuator spring biases the actuator against displacementxe2x80x94that is, the actuator spring urges the actuator in the direction towards the ball so that the end of the actuator is maintained within the notch in the ball spherical surface thereby tending to retain the ball in the open position.
When the valve has been moved to the open position, which is accomplished by rotating the valve ball stem that is rotatably received within the valve body, and the actuator extends within the notch in the spherical surface of the ball, fluid can continue to flow through the valve, the rate of fluid flow being substantially undiminished by the paddle that extends from the actuator into the fluid flow stream. If the rate of fluid flow through the stream reaches a predetermined velocity the impact of fluid against the paddle overcomes the bias of the actuator spring, permitting the actuator to move against the bias of the spring and to thereby cause the actuator to be withdrawn from the notch in the ball spherical surface. When the actuator is withdrawn, the ball is free to rotate in response to the closure spring bias rotating the ball from the opened to the closed position blocking further fluid flow through the valve. Thus, the valve functions in response to excess flow to shut off flow through the valve.
When the condition that has resulted in excess flow has been corrected, the valve can be moved back to the open position by rotating the ball to the fully open position at which time the actuator again extends within the notch in the ball spherical surface. The valve will remain in the open condition and permit fluid flow unless and until the flow again exceeds the predetermined maximum flow rate.
The maximum flow rate is predetermined essentially by three factorsxe2x80x94that is, (1) the relative cross-sectional area of the paddle; (2) the shape of the paddle (the paddle could be cup-shaped to create more drag); and (3) the bias imposed by the actuator spring. In addition, there is certain drag or frictional resistance against the movement of the actuator in response to force applied by fluid flow against the paddle. Using the principles of the invention, the dimensions of the valve components as well as the bias of the actuator spring can be calculated so that the valve can be designed to accurately respond to a predetermined excess fluid flow rate. Obviously, the nature of the fluid will enter into calculating the design parameters since a heavier fluid will exert more force against the paddle than a lighter fluid flowing at the same velocity.
For a better understanding of the invention reference may be had to the following drawings taken in conjunction with the detailed description of the preferred embodiment.